#pragma once

#include <iostream>
#include <queue>
#include <pthread.h>
#include "Task.hpp"
#include "Log.hpp"

#define NUM 6

class ThreadPool
{
private:
    int num;
    bool stop;
    std::queue<Task> task_queue;
    pthread_mutex_t lock;
    pthread_cond_t cond;

    ThreadPool(int _num = NUM)
        : num(_num), stop(false)
    {
        pthread_mutex_init(&lock, nullptr);
        pthread_cond_init(&cond, nullptr);
    }
    ThreadPool(const ThreadPool &){}; //禁止拷贝
    static ThreadPool *single_instance;
public:
    static ThreadPool* getinstance()
    {
        static pthread_mutex_t _mutex = PTHREAD_MUTEX_INITIALIZER;
        if(single_instance==nullptr)
        {
            pthread_mutex_lock(&_mutex);
            if(single_instance== nullptr)
            {
                single_instance = new ThreadPool();
                single_instance->InitThreadPool();
            }
            pthread_mutex_unlock(&_mutex);
        }
        return single_instance;
    }
    bool IsStop()
    {
        return stop;
    }
    bool TaskQueueIsEmpty()
    {
        return task_queue.size() == 0 ? true : false;
    }
    void Lock()
    {
        pthread_mutex_lock(&lock);
    }
    void Unlock()
    {
        pthread_mutex_unlock(&lock);
    }
    void ThreadWait()
    {
        pthread_cond_wait(&cond, &lock);
    }
    void ThreadWakeUp()
    {
        pthread_cond_signal(&cond);
    }
    static void *ThreadRoutine(void *args)
    {
        ThreadPool *tp = (ThreadPool *)args;
        while (true)
        {
            Task t;
            tp->Lock();
            while (tp->TaskQueueIsEmpty())
            {
                tp->ThreadWait();
            }
            tp->PopTask(t);
            tp->Unlock(); // 锁只为“取任务”，不为“干任务”。
            t.ProcessOn();
        }
    }
    bool InitThreadPool()
    {
        for (int i = 0; i < num; i++)
        {
            pthread_t tid;
            if (pthread_create(&tid, nullptr, ThreadRoutine, this) != 0)
            {
                LOG(FATAL, "pthread_create error");
                return false;
            }
        }
        LOG(INFO, "init threadpool success");
        return true;
    }
    void PushTask(const Task &task)
    {
        Lock();
        task_queue.push(task);
        Unlock();
        ThreadWakeUp();
    }
    void PopTask(Task &task)
    {
        task = task_queue.front();
        task_queue.pop();
    }
    ~ThreadPool()
    {
        pthread_mutex_destroy(&lock);
        pthread_cond_destroy(&cond);
    }
};

ThreadPool* ThreadPool::single_instance = nullptr;